A.2 B.3 C.4
A.隔離開(kāi)關(guān) B.負(fù)荷開(kāi)關(guān) C.空氣開(kāi)關(guān)
A.體積小 B.出線回路數(shù)少 C.不經(jīng)濟(jì)